An efficient method for improving the stability of Monascus pigments using ionic gelation.

BACKGROUND: Monascus pigments (Mps) are easily impacted by heating, pH and light, resulting in degradation. In this study, Mps were encapsulated by the ionic gelation method with sodium alginate (SA) and sodium caseinate (SC), as well as CaCl2 as a crosslinker. The encapsulated Mps SA/SC in four proportions (SA/SC: 1/4, 2/3, 3/2, 4/1, w/w). Then, the encapsulation efficiency and particle size of the SA/SC-Mps system were evaluated to obtain the optimal embedding conditions. Finally, the effects of heating, pH, light and storage on the stability of non-capsulated Mps and encapsulated Mps were assessed. RESULTS: SA/SC = 2/3 (AC2) had higher encapsulation efficiency (74.30%) of Mps and relatively small particle size (2.02 mm). The AC2 gel beads were chosen for further investigating the stability of encapsulated Mps to heating, pH, light and storage. Heat stability experiments showed that the degradation of Mps followed first-order kinetics, and the encapsulated Mps had lower degradation rates than non-capsulated Mps. Encapsulation could reduce the effect of pH on Mps. The effects of ultraviolet light on the stability of Mps were considered, and showed that the retention efficiency of encapsulated Mps was 22.01% higher than that of non-capsulated Mps on the seventh day. Finally, storage stability was also evaluated under dark refrigerated conditions for 30 days, and the results indicated that encapsulation could reduce the degradation of Mps. CONCLUSION: This study has proved that AC2 gel beads can improve the stability of Mps. Thus, the ionic gelation method is a promising encapsulation method to improve the stability of Mps. © 2023 Society of Chemical Industry.

Photophysical Switching between Aggregation-Induced Phosphorescence and Dual-State Emission by Isomeric Substitution.

It is attractive but highly challenging to achieve controllable regulation of photophysical properties of pure organic luminogens, due to distinct work mechanisms and molecular structures. Here, a strategy to regulate in a controllable way the emission behavior of luminogens is reported, according to which long-lived aggregation-induced emission (AIE) can be switched to short-lived dual-state emission (DSE) by an isomer-based substitution reaction. Three luminogens with sharply different photophysical behaviors, including aggregation-induced phosphorescence and dual-state fluorescence emission, were obtained through a substitution reaction with three isomers. Freely rotating structures are attributed to aggregation-induced phosphorescence behavior, whereas twisted rigidification of the molecule greatly contributes to its dual-state emission phenomenon. This work contributes to the controlled regulation of photophysical behaviors through simple reactions and provides a solid evidence to support the key role of the prohibition of intramolecular rotation in aggregation-induced emission process and molecular design of dual-state emitters.

Rational Design of Dual-State Emission Luminogens with Solvatochromism by Combining a Partially Shared Donor-Acceptor Pattern and Twisted Structures.

We report a general design strategy for a new class of luminogens with dual-state emission (DSEgens) that are brightly emissive in both the solution and solid state, with solvatochromism properties, by constructing a partially shared donor-acceptor pattern based on a twisted molecule. The DSEgens with bright fluorescence emission in both the solid and solution state demonstrate a unique solvatochromism behaviour depending on solvent polarity and thus may have applications in anti-counterfeiting.

Elevation-associated pathways mediate aquatic biodiversity at multi-trophic levels along a plateau inland river.

Aquatic biodiversity plays a significant role in maintaining the ecological balance and the overall health of riverine ecosystems. Elevation is an important factor influencing biodiversity patterns. However, it is still unclear through which pathway elevation influences riverine biodiversity at different trophic levels. In this study, the elevation-associated pathways affecting aquatic biodiversity at different trophic levels were explored using structural equation modeling (SEM) and taking the Bayin River, China as the case. The results showed that the elevational patterns were different among aquatic organisms at different trophic levels. For macroinvertebrates and bacteria, the pattern was hump-shaped; while for phytoplankton and zooplankton, it was U-shaped. Building upon these observed elevational patterns, our investigation delved into the direct and indirect pathways through which elevation influences aquatic biodiversity. We found that elevation exerts an impact on aquatic biodiversity via indirect pathways. For all aquatic organisms investigated, the major pathway through which elevation influences biodiversity is mediated by water temperature and water quality. For aquatic organisms at higher trophic levels, like macroinvertebrates and zooplankton, the crucial pathway is also mediated by the landscape. The results of this study contributed to understanding the effects of elevation on aquatic organisms at different trophic levels and provided an important basis for the assessment of riverine biodiversity at large scales.

Attribution Assessment and Prediction of Runoff Change in the Han River Basin, China.

The ecological environment and water resources of the Han River Basin (HRB) are incredibly susceptible to global warming. Naturally, the analysis of future runoff in HRB is believed to offer a theoretical basis for water resources management and ecological protection in HRB. The purpose of this study is to investigate and forecast the effects of climate change and land use change on runoff in the HRB. This study uses CMIP6 data to simulate three future climate change scenarios (SSP126, SSP245 and SSP585) for changes in precipitation and temperature, a CA-Markov model to simulate future land use change scenarios, and the Budyko framework to predict future runoff changes. The results show that: (1) Between 1974 and 2014, annual runoff (R) and annual precipitation (P) in the HRB decline not so significantly with a rate of 1.3673 mm/a and 1.2709 mm/a, while maximum temperature (Tmax) and minimum temperature (Tmin) and potential evapotranspiration (E0) show a non-significantly increasing trend with 0.0296 °C/a, 0.0204 °C/a and 1.3313 mm/a, respectively. Precipitation is considered as main contributor to the decline in Han River runoff, accounting for 54.1%. (2) In the HRB, overall precipitation and temperature are estimated to rise in the coming years, with all other hydrological variables. The comparison of precipitation rise under each scenario is as follows: SSP126 scenario > SSP585 scenario > SSP245 scenario. The comparison of the temperature increase under each scenario is as follows: SSP585 scenario > SSP245 scenario > SSP126 scenario. (3) In the HRB, farmland and grassland land will continue to decline in the future. The amount of forest acreage is projected to decline but not so significantly. (4) The future runoff of the HRB shows an increasing trend, and the future runoff varies in different scenarios and periods. Under the land use scenarios of maintaining LUCC1992-2014 and LUCC2040 and LUCC2060, the R change rates in 2015-2040 are 8.27-25.47% and -8.04-19.35%, respectively, and the R in 2040-2060 are 2.09-13.66% and 19.35-31.52%. At the same time, it is very likely to overestimate the future runoff of the HRB without considering the changes in the land use data of the underlying surface in the future.

Deep Learning-Based Model Significantly Improves Diagnostic Performance for Assessing Renal Histopathology in Lupus Glomerulonephritis.

Background: Assessment of glomerular lesions and structures plays an essential role in understanding the pathological diagnosis of glomerulonephritis and prognostic evaluation of many kidney diseases. Renal pathophysiological assessment requires novel high-throughput tools to conduct quantitative, unbiased, and reproducible analyses representing a central readout. Deep learning may be an effective tool for glomerulonephritis pathological analysis. Methods: We developed a murine renal pathological system (MRPS) model to objectify the pathological evaluation via the deep learning method on whole-slide image (WSI) segmentation and feature extraction. A convolutional neural network model was used for accurate segmentation of glomeruli and glomerular cells of periodic acid-Schiff-stained kidney tissue from healthy and lupus nephritis mice. To achieve a quantitative evaluation, we subsequently filtered five independent predictors as image biomarkers from all features and developed a formula for the scoring model. Results: Perimeter, shape factor, minimum internal diameter, minimum caliper diameter, and number of objects were identified as independent predictors and were included in the establishment of the MRPS. The MRPS showed a positive correlation with renal score (r = 0.480, p < 0.001) and obtained great diagnostic performance in discriminating different score bands (Obuchowski index, 0.842 [95% confidence interval: 0.759, 0.925]), with an area under the curve of 0.78-0.98, sensitivity of 58-93%, specificity of 72-100%, and accuracy of 74-94%. Conclusion: Our MRPS for quantitative assessment of renal WSIs from MRL/lpr lupus nephritis mice enables accurate histopathological analyses with high reproducibility, which may serve as a useful tool for glomerulonephritis diagnosis and prognosis evaluation.

Development of a rapid and accurate CRISPR/Cas13-based diagnostic test for GII.4 norovirus infection.

Genogroup II genotype 4 (GII.4) norovirus causes acute gastroenteritis in children, and its infection is more severe than that of other genotypes. Early and precise detection and treatment are critical for controlling its spread and reducing the severity of infection. In this study, a rapid and efficient isothermal assay for the GII.4 norovirus detection (GII.4-CRISPR detection) was developed based on the CRISPR/Cas13a system. The assay can be applied without expensive instrumentation, and the results can be read via both fluorescence and lateral flow strip (LFS). The analytical sensitivity of this assay was 5 copies/reaction, and there was no cross-reaction with other genotypes of norovirus or other clinically common pathogens. There was a coincidence rate of 100% between our assay and commercial quantitative polymerase chain reaction. GII.4-CRISPR detection improves upon the shortcomings of some previously established molecular methods of detection, particularly with regard to accessibility. It provides an alternative tool for outbreak control and early diagnosis of GII.4 norovirus infection.

Genetic and clinical characteristics of genital Chlamydia trachomatis infection in Guangzhou, China.

BACKGROUND: Genital Chlamydia trachomatis (CT) is one of the most common agents of sexually transmitted infections and can cause severe disorders. This study aimed to analyse the genetic and clinical characteristics of genital CT infection among women in Guangzhou, China. METHODS: From September 2020 to August 2021, a total of 8955 female patients were enrolled in this study. The presence of genital CT was detected by real-time PCR, and 273 positive samples were randomly selected for further genetic and clinical characteristics analysis. RESULTS: The positive rate of genital CT infection was 7.5% (670/8955), with the highest rate in women aged 21-30 years. A total of 8 genotypes were identified: DH, J, K, and recombinant genotype Ba/D. The predominant genotype was J (n = 78, 28.6%), followed by E (n = 63, 23.1%), F (n = 48, 17.6%), and D (n = 38, 13.9%). Abnormal vaginal discharge (n = 165, 61.8%), cervical columnar epithelial ectopy (n = 124, 46.4%), vaginal itching (n = 77, 28.8%), and lower abdominal pain (n = 61, 22.8%) were the predominant symptoms. Additionally, genotype G infection exhibited a significantly higher rate of abnormal vaginal discharge (P = 0.03) and genotype D infection exhibited a higher white blood cell count (P = 0.01) than the other genotypes. Phylogenetic analysis revealed a total of 20 variants with 25 mutation positions and the H2 variant in four patients was first discovered in our study. CONCLUSIONS: Genotypes J, E, F, and D were the major genotypes of genital CT in Guangzhou, and they manifested as abnormal vaginal discharge, cervical columnar epithelial ectopy, vaginal itching, and lower abdominal pain. The present study provides guidance for future integrated interventions to reduce the burden of genital CT infection and accelerate the development of vaccines.

One-Step Reverse-Transcription Recombinase Polymerase Amplification Using Lateral Flow Strips for the Detection of Coxsackievirus A6.

Hand, foot, and mouth disease (HFMD) is a common infectious disease affecting mainly children under 5 years of age. Coxsackievirus A6 (CVA-6), a major causative pathogen of HFMD, has caused outbreaks in recent years. Currently, no effective vaccine or antiviral treatments are available. In this study, one-step reverse-transcription recombinase polymerase amplification (RT-RPA), combined with a disposable lateral flow strip (LFS) assay, was developed to detect CVA-6. This assay can be performed in less than 35 min at 37°C without expensive instruments, and the result can be observed directly with the naked eye. The sensitivity of the RT-RPA-LFS was 10 copies per reaction, which was comparable to that of the conventional real-time quantitative polymerase chain reaction (qPCR) assays. Moreover, the assay specificity was 100%. The clinical performance of the RT-RPA-LFS assay was evaluated using 142 clinical samples, and the coincidence rate between RT-RPA-LFS and qPCR was 100%. Therefore, our RT-RPA-LFS assay provides a simple and rapid approach for point-of-care CVA-6 diagnosis.

Prevalence of GII.4 Sydney Norovirus Strains and Associated Factors of Acute Gastroenteritis in Children: 2019/2020 Season in Guangzhou, China.

Norovirus, the leading cause of non-bacterial acute gastroenteritis (AGE) worldwide, is constantly mutating. Continuous monitoring of the evolution of epidemic genotypes and emergence of novel genotypes is, therefore, necessary. This study determined the prevalence and clinical characteristics of norovirus strains in AGE in Guangzhou, China in 2019/2020 season. This study included children aged 2-60 months diagnosed with AGE in Guangzhou Women and Children Hospital, from August 2019 to January 2020. Norovirus was detected by real-time polymerase chain reaction and clinical data were obtained. Genotyping and phylogenetic analyses were performed with partial gene sequence fragments located within the open reading frames 1 and 2. During the study period, 168 children (61.3% males) were confirmed as norovirus infectious AGE. The main symptoms were diarrhoea and vomiting and 38 patients (22.6%) had seizures. Norovirus was mainly prevalent in October and November, and GII.4 Sydney[P31] was the major genotype circulating in Guangzhou. The phylogenetic tree showed that the Guangzhou strains had high homology with the strains circulating in 2017-2019 worldwide. GII.4 Sydney was the main prevalent norovirus genotype in Guangzhou from August 2019 to January 2020, which had more severe diarrhoea than those of other genotypes. These findings provide a valuable reference for the prevention, control, and treatment of norovirus in the future.

A phosphorescence "turn-on" probe for the detection and imaging of Al3+ based on aggregation-induced emission.

Aggregation-induced emission luminogens (AIEgens) have been widely used to design fluorescent probes for chemosensing and bioimaging. However, it is still challenging to design long-lived AIE-active probes due to the lack of aggregation-induced phosphorescence (AIP) luminogens. In this work, we design and synthesize a long-lived molecular probe with aggregation-induced phosphorescence property for aluminum ion-specific detection by introducing multiple carboxylic acid groups in a unique twisted molecular skeleton, and develop a first phosphorescent detection method for aluminum ion based on aggregation-induced emission mechanism. The introduction of six carboxylic acid groups into the probe not only significantly enhances the water-solubility but also provides specific recognition unit for aluminum ions via complexation. The probe shows a very sharp emission enhancement in the presence of aluminum ions via aluminum ion-triggered aggregation-induced emission. The cytotoxicity test of the probe shows its biocompatible nature, and further imaging results in live human cells and roots of live Arabidopsis thaliana demonstrates that the designed AIP-active probe is capable of monitoring aluminum ions in complex biological systems. This work proposes a general design strategy for AIP-active probes, and provides valuable use of these AIP-active probes in bioimaging.

Halogenated tetraphenylethene with enhanced aggregation-induced emission: an anomalous anti-heavy-atom effect and self-reversible mechanochromism.

Halogenated tetraphenylethene derivatives show a unique anti-heavy-atom effect where introducing heavy halogens like bromine greatly improves the fluorescence quantum yield upon aggregation, contrary to the classic heavy-atom effect. The unique self-reversible mechanochromism of brominated TPE is attributed to re-generation of halogen-halogen bonding after its breakage.

A water-soluble molecular probe with aggregation-induced emission for discriminative detection of Al3+ and Pb2+ and imaging in seedling root of Arabidopsis.

Luminogens with aggregation-induced emission (AIE) have been used to develop a new type of molecular probes based on analyte-triggered aggregation, but it still remains a challenge to design water-soluble AIE-active probe for specific detection of metal ions. Herein, we designed and synthesized a water-soluble molecular probe with AIE property for discriminative detection of aluminum ion and lead ion. Four carboxylic acid groups were incorporated into a tetraphenylethylene unit to enhance the coordination affinity and increase water-solubility in aqueous solution. The designed probe can be selectively lighted up by aluminum ion and lead ion via coordination-triggered AIE process. Discrimination of aluminum ion and lead ions based on the probe can be achieved in quantitative manner with the assistance of suitable masking reagents. This probe was further used to image aluminum ions in living cells of seedling roots of Arabidopsis, and the results showed that this probe is capable of imaging aluminum ions in living cells avoiding the interference of lead ions, and is suited for long-term imaging due to its excellent photostability. This work expands the application scope of AIE-active probes in discriminative detection of metal ions, and provides a design direction for water-soluble AIE probes to avoid the false signals from self-precipitation under physiological conditions.